Transmission and Distribution line MCQ Part-7

1. Transmission line are transposed to_____________.

a. Prevent short-circuit between any two lines

b. Reduce skin effect

c. Prevent interference with neighbouring  telephone lines

d. Reduce corona loss

2. Transposition of transmission line is done to_________.

a. Balance line voltage drop 

b. Reduce line loss

c. Reduce corona

d. Reduce skin effect

3. High voltage transmission lines are transported because then_______.

a. Voltage drop in the lines can be minimized

b. Corona losses can be minimized

c. Phase voltage imbalances can be minimized

d. Computation of inductance becomes easier

4. The concept of an electrically short, medium and long line is primarily based on the___________.

a. Wavelength of the line

b. Nominal voltage of the line

c. Power transmitted over the line

d. Physical length of the line

 

5.  Equivalent x model is quite suitable for analyzing the performance of transmission line of_____________.

a. 50 km length

b. 250 km length

c. 150 km length

d. All of the above length

6. which of the following is neglected while analyzing a short transmission line ?

a. Series impedance

b. Power losses

c. Shunt admittances

d. None of the above

7. In modelling the equivalent circuit of a short length overhead transmission line, the line resistance and inductance are only considered because line capacitance to ground is________.

a. Infinite

b. Finite but very small

c. Equal to zero

d. Finite but very large

8. As compared to sending-end voltage, the receiving-end voltage of a short line under no-load condition is_________.

a. Lower

b. Higher

c. Remains the same

 

9.  Which of the following voltage regulation is considered to be the best ?

a. 2%

b. 30%

c. 70%

d. 98%

10. The regulation of a line at full load 0.8 pf lagging is 12%.The regulation at full-load 0.8 pf leading can be________.

a. 4%

b. 12%

c. 18%

d. 24% 

11. If in a short transmission line, resistance and inductive reactance are found to be equal and regulation appears to be zero, then the load will_______.

a. Be 0.707 lagging

b. Be 0.707 leading

c. Have unity power factor

d. Have zero power factor 

12. For a short line if the receiving-end voltage is equal to sending-end voltage under loaded conditions__________.

a. The receiving-end power factor is leading

b. The sending-end power factor is unity

c. The receiving-end power factor unity

d. The sending-end power factor leading

13. A single phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500A at 300 V. The sending-end power factor is______.

a. 0.6 lagging

b. 0.8 leading

c. 0.8 lagging

d. Unity

14. For an ac transmission line of length not exceeding 80 km, it is usual to lump the capacitance at_______.

a. Any convenient point 

b. The receiving end

c. The midpoint

d. The sending end

15. If L,C and Y are the inductance, capacitance and shunt admittance of a line per unit length, then for length l.

a. The shunt admittance is Y/l

b. The inductance is L/l

c. The shunt admittance is Y.l

d. The capacitance is C/l

16. Under no-load conditions, the current in a transmission line is because of_________.

a. Back flow from earth

b. Corona effect

c. Capacitance effect

d. Proximity effect

17. In a long transmission line under no-load condition________.

a. The sending-end voltage is less than the receiving-end voltage

b. The sending-end voltage is equal to the receiving-end voltage

c. The receiving-end voltage is less than the sending-end voltage

d. None of these

18. When is the Ferranti effect on long overhead lines experienced ?

a. The power factor is unity

b. The line is heavily loaded

c. The line is fully loaded

d. The line is lightly loaded

 

19. Ferranti effect happens in transmission line when the line is_______.

a. Long and unloaded

b. Long and loaded

c. Short and loaded

d. None of these

20. The ABCD constants of a 3-phase transposed transmission line with linear and passive elements__________.

a. Never equal

b. A and D are equal 

c. Are always equal

d. B and C are equal

21. The values of A, B, C and D constants for a short transmission line are respectively__________.

a. 1, 1, Z and 0

b. 0, 1, 1 and Z

c. Z, 0, 1 and 1 

d. 1, Z, 0 and 1

 

22. For a transmission line with resistance R, reactance X and negligible capacitance, the generalised constant A is_________.

a. R + X

b. 1

c. R + j X

d. 0

23. The value of the 'A' parameter of a transmission line_______.

a. Is independent

b. Increases with the increase in length of the line 

c. Decreases with the increase in line length

24. For a medium length transmission line, A is__________.

a. Equal to D

b. Equal to C

c. Equal to B

d. Not equal to any of the above

25. For transmission line which one of the following relations is true?

a. AD - BC = 0

b. -AD - BC = 1

c. AD - BC = 1

d. AD - BC = -1

26. Which one of the following equations is correct ?

a. -AB + CD = -1

b. -AD + BC = -1

c. AD + CD =1

d. AB - CD = -1

Transmission and distribution line MCQ Part-1

Transmission and Distribution line MCQ Part-2

Transmission and Distribution line MCQ Part-3

Transmission and Distribution line MCQ Part-4

Transmission and Distribution line MCQ Part-5

Transmission and Distribution line MCQ Part-6